IRS Publication 5845 – IRS Forms, Instructions, Pubs 2026 – Are you starting a new business, changing your company structure, or wondering if your current Employer Identification Number (EIN) is still valid? IRS Publication 5845 (revised July 2023) answers the most common question business owners ask: “Do I need a new Employer Identification Number?”
This official IRS guide remains the authoritative source as of February 2026. The IRS continues to list Publication 5845 as current on its Forms, Instructions, and Publications page, and its rules align with the dedicated “When to Get a New EIN” resource (last reviewed November 21, 2025).
Download the official PDF here: IRS Publication 5845 (July 2023)
In this SEO-optimized guide, you’ll find clear, entity-by-entity breakdowns, quick-reference tables, real-world examples, and step-by-step application instructions—so you stay compliant and avoid costly mistakes.
What Is an EIN and Why Does It Matter?
An Employer Identification Number (EIN) is a unique nine-digit federal tax ID assigned by the IRS to businesses, estates, trusts, and other entities. It functions like a Social Security number for your business and is required for:
- Hiring employees
- Opening business bank accounts
- Filing employment, excise, or income tax returns
- Operating as a partnership, corporation, LLC (in most cases), or certain trusts/estates
Key IRS rule from Publication 5845:
You generally need a new EIN when your business ownership or structure changes.
You do NOT need a new EIN just because you change your business name, location, or responsible party.
Quick-Reference Table: Do You Need a New EIN?
| Business Type | YES – Get New EIN | NO – Keep Existing EIN |
|---|---|---|
| Sole Proprietor | • Bankruptcy • Incorporate • Add partners (becomes partnership) • Buy/inherit existing business |
• Change name • Change/add locations • Run multiple businesses |
| Corporation | • New charter from secretary of state • Become/use subsidiary EIN • Convert to partnership/sole prop • New corp created after statutory merger |
• Division of corp • Surviving corp in merger • Bankruptcy • Name/location change • Elect S-corp status • Reorg that only changes identity/place • State-level conversion (structure unchanged) |
| Partnership | • Incorporate • One partner takes over as sole prop • End old partnership & start new one |
• Bankruptcy • Name/location change • Ownership change that doesn’t terminate partnership under IRC §708 |
| LLC | • Terminate LLC & form new corp/partnership • Single-member LLC must file employment/excise taxes (and wasn’t already) |
• Name/location change • Classified as disregarded entity/branch with no employees/excise tax • Partnership-to-LLC conversion (same classification) • Tax election change to corp/S-corp (no structure change) |
| Estate | • Trust created from estate funds (not continuation) • Estate operates business after owner’s death |
• Administrator/executor name/address change |
| Trust | • Grantor creates multiple trusts (EIN per trust) • Trust becomes estate • Living/inter vivos → testamentary trust • Living trust distributes to residual trust • Revocable → irrevocable trust |
• Trustee change • Grantor/beneficiary name/address change |
Detailed Guidance by Business Type (Direct from Pub 5845)
Sole Proprietors
Most sole proprietors use their Social Security Number (SSN) instead of an EIN unless they have employees or specific filing requirements. However, Publication 5845 states you must obtain a new EIN in the four situations listed in the table above.
Example: Sarah runs a freelance graphic design business as a sole prop. She incorporates as “Sarah Designs Inc.” → She needs a new EIN.
Corporations
Corporations are strict about structure changes. A new charter or becoming a subsidiary almost always triggers a new EIN.
Partnerships
Partnership terminations under IRC rules (especially §708) are a frequent trigger. Note the specific exception for 50%+ ownership changes within 12 months that do not terminate the partnership.
Limited Liability Companies (LLCs)
LLCs are classified by the IRS as disregarded entities, partnerships, or corporations. The classification—not the state LLC filing—determines the EIN rule. Publication 5845 and the 2025 “When to Get a New EIN” page both emphasize checking your federal tax classification.
Estates & Trusts
These fiduciary entities have unique rules focused on creation of new trusts or conversion between estate and trust status.
Common Scenarios Business Owners Ask About
- Q: I just changed my business name. Do I need a new EIN?
A: No. Visit the IRS Business Name Change page for required actions (usually just update your filings). - Q: My LLC converted to a corporation at the state level. New EIN?
A: Only if the federal tax classification actually changed. State conversion alone with no structure change = keep your EIN. - Q: I declared bankruptcy. New EIN?
A: Yes for most entities (especially sole props and partnerships). Corporations generally do not need one for bankruptcy. - Q: I bought an existing business. Can I keep the seller’s EIN?
A: No—purchasing an existing business you operate as a sole proprietorship requires a new EIN.
How to Apply for a New EIN (Free & Fast)?
The IRS makes it simple and free:
- Online (recommended) – Apply directly on IRS.gov (instant approval for most U.S. applicants). Only one EIN per day per responsible party.
- Form SS-4 – Fax or mail if you can’t apply online.
- International applicants – Phone or fax options available.
Important tips:
- Apply after forming your entity with your state.
- Have your legal formation documents ready.
- Never pay a third-party service to get an EIN—the IRS provides it free.
Official application page: Get an Employer Identification Number
Frequently Asked Questions (FAQs)
- Is Publication 5845 still current in 2026?
Yes. The IRS continues to publish and reference the July 2023 revision with no new edition released. - Do I need a new EIN every time I change my address?
No—only ownership or structure changes matter. - Can I use the same EIN for multiple businesses?
Sole proprietors can use one EIN for multiple sole-prop businesses, but corporations, partnerships, and LLCs taxed separately usually need their own. - What if I’m not sure?
Use the IRS interactive tools or consult a tax professional/CPA. Incorrect EIN usage can delay tax filings and banking.
Final Thoughts & Next Steps
IRS Publication 5845 provides crystal-clear guidance to help you determine whether you need a new Employer Identification Number. Whether you’re a sole proprietor incorporating, a partnership adding members, or an LLC changing its tax classification, understanding these rules prevents compliance headaches.
Action steps today:
- Download Publication 5845
- Review the “When to Get a New EIN” page: irs.gov/when-to-get-a-new-ein
- Apply online if you need a new EIN
- Bookmark IRS.gov/EIN for future reference
Disclaimer: This article summarizes official IRS guidance for informational purposes only. Tax rules can be complex—always verify the latest information directly on IRS.gov or consult a qualified tax advisor or attorney. The content is based on Publication 5845 (July 2023) and supporting IRS resources current as of February 2026.
Need help with a specific scenario? Feel free to ask in the comments or contact the IRS EIN assistance line. Staying compliant has never been easier when you follow the official rules in Publication 5845!
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